Or just using one on the fuel rail?

 

Fuel Pressure gauge isn't real useful. It is nice to have maybe once or twice, but the vast majority of the time it is useless.

If you are running the stock FPR then don't even bother. If you have an aftermarket adjustable FPR you will need some kind of gauge to set the base pressure, then you don't have to mess with it again.

 

I'll be using an aftermarket fpr. I was just more worried about a fuel pump going bad or something.

Just trying to do my homework!

 

With the EMS you can set an O2 warning output threshold, which I feel is much more useful than the fuel pressure. Go to Options/Configure Outputs, pick one of the unused LS outputs and wire up a simple 12V LED to it, then configure the thresholds so it will light up if the O2 is too lean when the engine load is more than 5PSI or whatever you want.

You can set the warning light to come on based on engine RPM, boost level and a few other parameters, but I think just setting it based on boost and the O2 Lean limit is easiest.

For example, I have mine set to turn on a light on the dash if the boost is higher than 10PSI and the O2 is leaner than 12.8:1. You can set the parameters however you like, and they can be different for pump or race gas maps, since you might want a warning for a different O2 limit between pump gas and race gas.

Hope this helps